EP 1 269 911 A2 discloses a system and method for selecting physiological data from a plurality of physiological data sources. The system comprises several sensors and a selection algorithm which selects the measurements from one of the sensors and outputs the respective measurement results. A first sensor measures a physiological trait and a second sensor will also measure the physiological trait but with a different physiological characteristic. The selection algorithm selects that physiological data which provides a heart rate which is most suitable for the output. In particular, the measurement results from those sensors which have the greatest accuracy are selected.
EP 2 520 222 A1 discloses a biological information processing device. The biological information processing device has a sensor for measuring a pulse rate of a user and a detector for detecting a motion of a user. An estimation unit is provided for estimating a pulse based on the measurements of the motion detector. As long as a measurement of the pulse rate is possible, the output of the pulse rate sensor will be displayed. If the measurement is, however, not possible, then the estimated pulse rate as determined by the estimation unit will be displayed.
EP 2 116 183 A1 discloses a robust opto-electrical ear located cardiovascular monitoring device. The device comprises a first sensor based on a PPG technique for measuring a first cardiovascular signal and at least a second cardiovascular sensor based on an electrocardiography or an impedance cardiography method for measuring a second cardiovascular signal. The device further comprises a processing module for estimating the reliability of the cardiovascular sensor signals and selects one of the cardiovascular signals.
US 2012/0172684 A1 discloses a heart rate monitor having a heart rate sensor and a motion sensor. The motion sensor serves to detect a motion of a user. The detected motion is correlated in time with the signal from the hear rate sensor to provide a compensation signal in which the noise contribution due to motion is reduced.
The monitoring of a heart rate of a user for example by means of optical sensors is well known. Here, an optical sensor emits light into the skin of a user. The emitted light is scattered within the skin and reflected light exits the skin and is captured by an appropriate sensor. Based on the received signals from the sensor, the heart rate of a user can be determined.
Heart rate sensors are for example been used for fitness applications. These devices monitor the heart rate by means of chest belts or at the wrist or forearm of a user. As the heart rate monitor sensors are also used when the user is moving, in particular for fitness applications, the motion of the user can introduce motion artifacts in the measurements of the heart rate sensor. These motion artifacts may be considered as a heart beat such that the heart rate sensor can misinterpret these motion artifacts as heart beats leading to an incorrect heart rate.
EP 2 612 594 A2 discloses a heart rate monitor in form of a wrist watch type device. The heart rate monitor comprises an optical sensor for detecting the heart rate, a motion sensor for sensing changes in the position of the device with respect to the skin in order to compensate for noise. Furthermore, an accelerometer is provided to give information regarding the motion of the user with respect to the user's heart. A heart rate Kalman filter is used to compute a heart rate on the basis of signals obtained from the plurality of sensors.